See also s.v. ˀyš, ˀynyš and note that the latter is not the same word as this. (Technically this word is a second millennium BCE back-formation from the plural of the segholate noun *ˀinš.) Note in particular that the absolute form refers to "person, somone" whereas the determined form more generally to mankind (at least after OfA). See also s.v. br ˀnš, the more common usage.
See, too, discussions s.vv. ˀnšh, ˀnšy bytˀ, ˀynyš.